1. Technical Field
This invention relates in general to bicycle seat suspension and in particular to a shock-absorbing, seat post assembly that lowers the bicycle's center of gravity while riding.
2. Background Art
The prior art in the field of bicycle suspension seat posts can essentially be divided into two basic design categories: (1) a spring loaded linear design, similar in function to a pogo stick, that incorporates two telescoping tubes that compress straight downward utilizing an internal or external spring, or other shock absorbing material, such as those disclosed in U.S. Pat. Nos. 7,422,224 B2; 6,581,919 B2; 6,186,487 B1; 5,704,626; 5,236,170 and 5,236,169; or (2) a cantilever style design that allows the seat to pivot downwards toward the rear of the bicycle, such as those disclosed in U.S. Pat. Nos. 5,833,255; 5,346,235; U.S. Pat. No. 6,409,130 B1 and 5,833,255.
Previous efforts to develop practical and reliable suspension seat posts have been marginally successful, and have been the subject of two product safety recalls due to cracks in the seat post assembly. (See, generally Consumer Product Safety Commission Alert #02-208, Cane Creek “Thudbuster” Model, Jul. 24, 2002; Consumer Product Safety Commission Alert #5-543, Cannondale 1-X Bicycle Suspension Seat Post, Feb. 18, 2005). As a result, cantilever and pogo stick style seat posts designed for mountain bikes have never fully been accepted as part of the mainstream in the mountain biking community due to their complexity and unreliability.
While providing a suspension component in their design, no known pogo stick design allows the seat to move both down and backwards toward the rear of the bicycle. While the above mentioned pogo stick designs contemplate a means for adjusting the rate of tension on the internal suspension spring, none of the pogo stick designs utilize an adjustable hydraulic suspension damping shock to control the spring rebound rate (i.e. the rate of speed the shock spring returns to its fully extended position after being compressed) as the preferred embodiment does.
Of the four cantilever designs mentioned above, two incorporate an elastic polymer suspension component but have no spring. (U.S. Pat. Nos. 6,409,130 B1 and 5,833,255). Another cantilever design, U.S. Pat. No. 6,270,065 B1, incorporates a spring shock absorber at the center of the cantilever mounts instead of an elastic polymer. U.S. Pat. No. 6,270,065 B1 includes a means for adjusting the rate of tension on the internal suspension spring and contemplates the use of an internal damping shock to control the spring rebound, however its inventor concludes the use of a hydraulic damping shock is not essential for the invention. The preferred embodiment of this invention differs in that it utilizes both a spring and a hydraulic damping shock.
Another functional disadvantage of the cantilever design as opposed to the present embodiment is the cantilever design's scissor-like manner of compression, posing the hazard of crushed fingers or other small body parts to users during operation. The complexity of the motion of this design and the large number of components likewise increase the chance of product failure.